Improvement in center-boards



v A. G. CROSSMAN. -Impr0vment in Center-Boards.

Patented May 23,187].

UNITED STATEs PATENT DFFICE.

ALonZo e. OROSSMAN, or nunrmerron, new YORK, ASSIGNOR TO FRANKLIN M. CROSSMAN, OF SAME PLACE.

$pecification forming part of Letters Patent No. 115,l73, dated May 23, 1871.

I, ALONZO G. Oaossiran, of Huntington,

in the county of Suffolk and State of New York, have invented a certain Improvement in Center-Boards and Trunks for Vessels, of which the following is a specification:

N atm'e and Object of the Invention.

This invention relates to a center-board made in two parts, the parts being hinged together, and to a mode of construction of the trunk of the vessel to receive said center-board, by which greater strength and other advantages are secured, as hereinafter more fully set forth.

Description of the Accompanying Drawing.

General Description.

'A A is a trunk of a vessel to. receive the center-board, and is constructed in most respects like those now in ordinary use to receive the center-boards of vessels. B and G are the parts of the center-board, which are hinged together at the bottom, as shown, and the part B is also hinged to the forward end of the trunk, or to a standard which may be attached thereto. The part 0, besides being hinged at the bottom to the part B, is also hinged at the top to the stay D by means of alink or double hinge, E, in such a manner that, when the centenboard is raised up into the position shown in Fig. 1, the line of the bottom of the. center-board will be nearly or quite even and parallel with the line of the bottom of the keel; and when the center-board is lowered to the position shown in Fig. 2, the

after end will be lower than the forward end,

. as shown in said figure. The stay D is a piece of timber framed into the trunk AAfor the purpose of strengthening the trunk near the middle, and this stay and the trunk are also bolted together to give greater solidity to the structure. For this purpose this stay should be as broad as the opening in the center-board will allow, and the parts D and A should be well secured together, so as to give the greatest possible firmness.

The addition of this stay 1) is a feature of very great importance, because it strengthens the vessel at its weakest point, and gives great strength and solidity to those parts which receive the strain of the centenboard and hold it in place.

F Fare two side pieces or plates of metal bolted to the part B of the center board to receive the forward end of the part 0.

By carrying the hinge which unites the parts B and 0 down as low as possible, and so constructing it that it shall take the least amount of room consistent with the necessary strength, room may be made to extend the stay D down into the keelson, and this is de sirable where great strength is required.

' It may also be well upon some vessels, where obstructions are liable to get into the trunk and interfere with the working of the center board, to close up the opening at the top so as to prevent this result. This may be done by taking off the upwardly-projecting portion at the rear of the center-board and making the piece E of sufiicient breadth to fill the space between the sides of the trunk, in which case it may be made of wood with iron joints at the ends.

Claim.

Witnesses: Tnos. I. How Ln Wv 

